1. Field of the Invention
The present invention relates generally to image processing systems, image processing methods, and image processing apparatuses.
2. Description of the Related Art
Client/server systems in which a client terminal requests a server apparatus to perform information processing are known today. In the client/server system, load on the server apparatus can increase when the number of requests requesting to perform information processing issued to the server apparatus increases or when the server apparatus performs time-consuming information processing. As the load increases, performance of the server apparatus decreases and, as a result, responsiveness to a request decreases. To reduce load on a server apparatus such as that described above, a technique (load balancing scheme) that involves a plurality of server apparatuses and allocates a request requesting to perform information processing to a lightly-loaded one of the server apparatuses is known.
For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2002-342298) discloses a parallel load balancing scheme. In the parallel load balancing scheme, a client terminal includes a client load balancer. The client load balancer transmits a request requesting to establish a session to an initially-designated server apparatus and selects, based on a response to the session establishment request, a server apparatus that executes a task.
The initially-designated server apparatus includes a server load balancer. Upon receiving the session establishment request from the client load balancer, the server load balancer compares the number of sessions among a plurality of initially-designated server apparatuses to transmit a response to the session establishment request to the client load balancer and manage the numbers of the sessions.
The parallel load balancing scheme described can adjust the load balance among the server apparatuses autonomously.
However, conventional load balancing schemes and the parallel load balancing scheme disclosed in Patent Document 1 adjust load balance among a plurality of server apparatuses by allocating information processing to a lightly-loaded server apparatus of the server apparatuses. Accordingly, even if the load balance is adjusted, when load on each of the server apparatuses increases due to an increase in the number of client terminals, responsiveness of a system, in its entirety, decreases.
Accordingly, when a conventional load balancing scheme or the parallel load balancing scheme disclosed in Patent Document 1 is used, there arises the need for adding a server apparatus(es) to thereby increase the number of entities to which information processing can be allocated, thereby preventing a decrease in responsiveness that would otherwise be caused by an increase in the number of client terminals. Specifically, when a conventional load balancing scheme or the parallel load balancing scheme disclosed in Patent Document 1 is used, the need for adding a server apparatus(es) proportionally to an increase in the number of client terminals arises.
Therefore, there is a need for an image processing system, an image processing method, and an image processing apparatus capable of decreasing load on a server apparatus to which information processing can be allocated.